weird glass effect artifacts - Principled BSDF, Transmission 1
Nice cup! But it has 2 issues:

duplicated vertices
flipped normals

When you turn on Face Orientation in the overlays, you will see your cup is mostly red (flipped normals) and there is some flickering/pixel fight going on (duplicates).
To fix it select the cup, switch to edit mode, select all vertices with key A, then press M to open the merge context menu. There, select by distance to get rid of the duplicated vertices.
Then press SHIFT + N to recalculate the normals (outside).